The male driver of the Mitsubishi and a man and woman from the third vehicle were taken to hospital with minor to moderate injuries.
The body of the driver was this afternoon found by police divers inside the submerged vehicle, which was later winched out by crane while local Maori performed a blessing.
Police still wanted to hear from any witnesses who had not been interviewed yet.
Inspector Clifford Paxton said police were "very, very proud'' of the officer who stripped down to his underwear and dived into cold water to rescue the van's passenger
The man had disappeared under the water but when he re-surfaced the officer grabbed hold of him and they were carried by the current.
The officer managed to calm the man down and turn him onto his back.
After about half an hour focusing on flashlights being used by searchers on the shore, the officer managed to get them both to land.
They were taken to hospital with hypothermia. The police officer was discharged last night and was resting at home today.
"We are very, very proud of the officer's efforts; what he did was pretty outstanding,'' Mr Paxton said.
"He evaluated the situation, believed he could make a difference, and clearly he did make a difference. I have already had members of the public call me this morning to pass on their congratulations.''
The Maungatapu Bridge, which was cordoned off for much of the day, is now open to traffic.
Anyone with any information about the crash was asked to contact Tauranga police on (07) 577 4300.
